Treesearch

The climates of central and southern regions of São Paulo state (Brazil) are suitable for pathogens such as Puccinia psidii, which causes a common and serious disease in eucalyptus plantations less than 2 years old. We studied the genetic variability of P. psidii in commercial plantations of Eucalyptus species by random amplified polymorphic DNA molecular markers. All 56 isolates of P. psidii analyzed showed high polymorphism and there was no evidence of preferential infection in different plant tissues. In the analysis of pooled pustules according to the clone of origin, we observed the...

Cronartium flaccidum is a serious pathogen of twoneedle pines, especially of Pinus sylvestris, in northern Fennoscandia (Samils et al. 2010). The rust spreads via a number of alternate hosts in natural forests and gardens, among which species in genera Melampyrum, Pedicularis, Vincetoxicum, and Paeonia are the most important known ones (Gäumann 1959; Kaitera et al. 1999). In northern Europe, the most important species is Melampyrum sylvaticum (Kaitera et al. 2005), while in southern Europe the respective species is Vincetoxicum hirundinaria (Gäumann 1959). Cronartium ribicola is a common...

On August 24, 2009, while working in Rocky Mountain National Park (Estes Park, Colorado, USA) on the Conserving Limber Pine Genetic Diversity for Possible Future Restoration at Rocky Mountain National Park project (see Schoettle et al. 2011, 2013, in press), a crew from the U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station (RMRS) noticed a small limber pine (Pinus flexilis) with a dead top along Highway 36 near the Many Parks Curve (fig. 1). The tree was about 2 m tall and 7 to 10 cm in diameter at breast height (d.b.h., 1.37 m) and occurred at about 3,000 m...

Land managers have commonly sought to discourage or prohibit camping near surface waters (e.g., lakes, rivers, streams, and springs), imposing regulations that prohibit camping within a specified distance from water. As Griffin presents, these camping setbacks from water within Forest Service Wilderness areas currently range from 50 to 1,320 ft, with 100 ft as the most common prohibition, followed by 200 ft, which is the distance recommended by the national Leave No Trace and Tread Lightly programs. An earlier survey by Washburne and Cole (1983) reported the following percentages of agency...

Limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (Pinus aristata) are important components of forest ecosystems in the southern Rocky Mountains, United States. Both species are susceptible to white pine blister rust caused by the fungal pathogen Cronartium ribicola. However, very little is known about the relative resistance of the two species. In this study, we used artificial inoculation of seedlings to compare the relative susceptibilities of these two species. The objective of the inoculation test was to compare the performance of seedlings from bulk seedlots of limber...

The nonnative pathogen Cronartium ribicola, the cause of the lethal white pine blister rust (WPBR) disease, is spreading through limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (P. aristata) forests of the southern Rocky Mountains (USA). An integrated regional program - the Proactive Strategy - is characterizing the infestation and gaining ecological and genetic knowledge of these less well studied ecosystems. This knowledge will provide the science foundation for early interventions to mitigate the development of ecological impacts to the high mountain headwater ecosystems...

Drippy blight is an emergent disease of red oaks, caused by the interaction between a kermes scale insect (Allokermes galliformis) and a bacterium (Lonsdalea quercina subsp. quercina). Multi-locus sequence analysis was used to confirm the bacterial pathogen’s identity and its relationship to other phylogenetically related Enterobacteriaceae species. Further, Koch’s postulates were performed on sapling red oaks. Prior to the discovery of drippy blight disease in Colorado, in the United States, the bacterium was reported on oak trees in California but was limited to acorn infections. The...

Wilderness and other protected natural areas like national forests, parks and refuges are managed to provide high quality recreational opportunities while preserving natural resource conditions. In managing recreation visitation, land managers could allow visitors to create their own infrastructure of trails and campsites, or they could choose to apply an impact management strategy to provide an infrastructure that includes sustainably designed trails and campsites. Recreation ecology studies have repeatedly demonstrated that informal “visitor-created” trails and campsites are generally...

Allokermes galliformis (Riley) (Hemiptera: Kermesidae), sometimes referred to as the ‘pin oak kermes’, has emerged as a significant pest of red oaks grown in the Front Range area of eastern Colorado. Although kermes scales infrequently cause significant tree damage, a novel association exists between the pin oak kermes and the pathogenic bacterium Lonsdalea quercina subsp. quercina. Together, they produce drippy blight disease of red oaks which is characterized by significant branch dieback. Field studies were conducted in Boulder, CO during 2015–2016 to better understand the life history...

Whitebark pine (Pinus albicaulis) is very susceptible to white pine blister rust, caused by the fungal pathogen Cronartium ribicola. Operational programs to develop resistant populations of whitebark pine are underway. These programs rely on artificial inoculation of young seedlings and can evaluate hundreds of parent trees using seedling progeny in a relatively short time. The trial reported here was undertaken at Dorena Genetic Resource Center (Cottage Grove, Oregon, USA). Inoculation was very effective and produced a high incidence and severity of disease in the seedlings with 99.9...